OPINION:
General Stanley McChrystal is speaking out against the Obama administration's use of drone strikes, echoing previous warnings and clashing with the White House's carefully cultivated narrative:

To The Daily Telegraph, London:

It's very tempting for any country to have a clean, antiseptic approach, that you can use technology, but it's not something that I think is going to be an effective strategy, unless it is part of a wider commitment.

To Reuters:

They are hated on a visceral level, even by people who've never seen one or seen the effects of one.

To journalist Trudy Rubin:

[Drones are] a very limited approach that gives the illusion you are making progress because you are doing something.

And to television anchor Candy Crowley

It can lower the threshold for decision making to take action that at the receiving end, feels very different at the receiving end.

McChrystal offers a unique perspective on the debate surrounding drone strikes. Serving as the commander of Joint Special Operations Command (JSOC) from 2003 to 2008, he restructured the secretive unit to capture or kill hundreds of suspected militants and terrorists in Iraq, Afghanistan, and elsewhere.

During this time, he had the authority to deploy US forces into Pakistan - without prior approval from the White House - in order to capture or kill Osama bin Laden.

As commander of the international and US forces in Afghanistan from June 2009 to July 2010, he significantly tightened the rules of engagement for airstrikes in populated areas, noting, "Air power contains the seeds of our own destruction."

(Full disclosure: McChrystal served on the advisory committee of my recent report on US drone strikes, although that does not mean he agreed with my findings or recommendations.)

Although his candour is rare in his field, many of McChrystal's concerns are increasingly shared by active-duty and retired military officials with whom I've spoken.

The vast majority of these officers, who held a wide range of positions while in uniform, are deeply troubled by the Obama administration's ongoing drone wars for five reasons.

First, many believe that discrete military operations - such as drone strikes and special operations raids - are much easier, more responsive, and less risky than previously available uses of force.

However, they worry that civilian policymakers have lowered the threshold for the use of lethal force, often at the exclusion of other elements of power that are essential to achieving any strategic objective.

The capabilities of Special Operations Command (SOCOM) have improved and expanded so dramatically since 9/11 that its commander, Admiral William McRaven, sincerely characterised the mission to kill Osama bin Laden as dull: "From a military perspective this was a standard raid. And not very sexy."

If once-exceptional missions are now routine - there were 13 comparable raids in Afghanistan the night bin Laden was killed - then the major concern is that they become the default option, with limited consideration for their long-term consequences.

As General Peter Pace, former chairman of the Joint Chiefs of Staff, warned: "I worry about speed making it too easy to employ force ... too easy to take the easy answer - let's go whack them with special operations - as opposed to perhaps a more laborious answer for perhaps a better long-term solution."

Second, members of the special operations community constantly repeat the mantra of F3EAD, pronounced "feed," the acronym for "Find, Fix, Finish, Exploit, Analyse, Disseminate."

Found in US Army Field Manual 3-60 ("The Targeting Process"), F3EAD is a process to attempt to capture, kill, or influence (for example, sending a text message warning "we're watching you") specific high-value targets within a broader counterinsurgency campaign. While it may be necessary to kill these individuals, the preferred options are to place the targets under constant surveillance to better understand their networks, or to interrogate them to gather intelligence. One of the overriding imperatives of counterinsurgency missions is to constantly increase and refine situational awareness of the environment.

As Brigadier General Michael Nagata - who colleagues say has perhaps as good an insight into recent clandestine operations as anyone in the US military - noted in 2011: "The fundamental value in capturing the enemy is so that you have a better grasp of the environment.

The more you understand the environment, the more effective your choices will be." (Nagata was recently assigned to lead SOCOM, US Central Command, where presumably he will be able to put his theories into practice.) By that thinking, the problem with standoff airstrikes instead of riskier operations to capture suspected militants is that you cannot enhance your understanding of the villages or cities where strikes occur, much less adequately measure the effects.

As one naval officer described the current strategy: "All we do in Pakistan is the find, fix, finish; we can do that forever."

Nor do such strikes always finish the target: A senior official with extensive background in special operations told me that in 10 per cent of the airstrikes he has watched - whether from Hellfire missiles or 2000-pound bombs - the intended victim has simply walked or run away unharmed from a destroyed house or vehicle. "Squirters," they are called.

Third, most service members exposed to direct combat can describe the instances - or near-instances - of collateral damage and civilian casualties caused by US airstrikes, despite the procedural safeguards in place that attempt to prevent this.

Among the many mistakes and near-misses related to me: The tribal leader whose Jeep was accidentally destroyed by an Apache helicopter in western Baghdad; the tribal police in Paktika Province, Afghanistan, who were nearly targeted by a drone because they had gathered in a courtyard one evening; or the Afghan girl injured by the blast from a bomb that destroyed a neighbouring compound.

Having witnessed the inherent limits of air power, many military officials - who admittedly lack direct insight into the CIA's drone programme - often claim that the CIA doesn't "really know who they're killing".

Fourth, more than 2.6 million US service members have been deployed to the war zones of Iraq and Afghanistan, where 6633 US personnel and an estimated 140,000 Iraqi and Afghan civilians have lost their lives.

After witnessing such carnage firsthand, many military officials found how the White House has handled the constant promotion of the bin Laden raid troubling and offensive - especially after Obama vowed, "We don't spike the football." I have met very few people in uniform who think killing another person is in any way "tough" or "cool."

Finally, every military (and civilian) official says "you cannot capture or kill" your way out the problems caused by those who use violence to achieve political objectives. What McChrystal noted about Afghanistan - "You can kill Taliban forever, because they are not a finite number" - would apply to any of the groups currently targeted by the US. Yet, the perception exists that killing is the only thing happening in Pakistan, Yemen and Somalia, in part because the military has so little faith in the capabilities of the State Department, the US Agency for International Development, and/or the host nation.

During his confirmation hearing to become the director of central intelligence, John Brennan repeated his prior pledge regarding al-Qaeda - "We will destroy that organisation" - which, according to the latest State Department estimates, is growing to thousands of individuals among its various "affiliates".

This current US counterterrorism strategy of "mowing the grass" (as it's indelicately called) through indefinite drone strikes, without thinking through the likely second- and third-order effects, will never achieve its strategic objectives.

This highlights the question military planning staffs will pose to civilian policymakers who ask about bombing a target or individual: "And then what?" In the case of a campaign of drone strikes, the answer these military planners see is more drone strikes.

Military officials consider themselves the guardians and stewards for how military force is perceived and employed. Through the iterative process in which kinetic military options are discussed and debated, they offer their best professional advice, and then follow the orders of their civilian leaders.

At the same time, many military officials believe that the governmental and national conversation about what the US is achieving with drones has been wholly inadequate.

A navy captain recently summarised the general consensus of his peers in other services: "Drones are an example of technology outpacing our morality and thinking."

Thus, military officials increasingly believe that the Obama administration must think through its current practices and policies of targeted killings, and consider how they can be reformed, or risk others following in US footsteps.

Micah Zenko (@MicahZenko) is a fellow with the Centre for Preventive Action at the Council on Foreign Relations. He writes the blog Politics, Power, and Preventive Action.